MoviesDataSource.cs - MSP Boot Camp 2013

MoviesDataSource.cs

using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Windows.ApplicationModel.Resources.Core;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
using System.Collections.Specialized;
using System.Threading.Tasks;
using Windows.ApplicationModel;
using Windows.Storage;
using Windows.Data.Json;

// The data model defined by this file serves as a representative example of a strongly-typed
// model that supports notification when members are added, removed, or modified.  The property
// names chosen coincide with data bindings in the standard item templates.
//
// Applications may use this model as a starting point and build on it, or discard it entirely and
// replace it with something appropriate to their needs.

namespace KRATIBMoviesSample.Data
{
    /// <summary>
    /// Base class for <see cref="SampleDataItem"/> and <see cref="SampleDataGroup"/> that
    /// defines properties common to both.
    /// </summary>
    [Windows.Foundation.Metadata.WebHostHidden]
    public abstract class MovieDataCommon : Common.BindableBase
    {
        protected static Uri _baseUri = new Uri("ms-appx:///");

        public MovieDataCommon(String uniqueId, String title)
        {
            this._uniqueId = uniqueId;
            this._title = title;
        }

        private string _uniqueId = string.Empty;
        public string UniqueId
        {
            get { return this._uniqueId; }
            set { this.SetProperty(ref this._uniqueId, value); }
        }

        private string _title = string.Empty;
        public string Title
        {
            get { return this._title; }
            set { this.SetProperty(ref this._title, value); }
        }

        public override string ToString()
        {
            return this.Title;
        }
    }

    /// <summary>
    /// Generic item data model.
    /// </summary>
    public class MovieDataItem : MovieDataCommon
    {
        public MovieDataItem(String uniqueId, String title, String description, IEnumerable<string> genres, String rating,
            DateTime datePublished, MovieDataYear yearGroup, TimeSpan duration, String posterImagePath)
            : base(uniqueId, title)
        {
            this._description = description;
            this._genres = genres;
            this._datePublished = datePublished;
            this._yearGroup = yearGroup;
            this._duration = duration;
            this._posterImagePath = posterImagePath;
        }

        private string _description = string.Empty;
        public string Description
        {
            get { return this._description; }
            set { this.SetProperty(ref this._description, value); }
        }

        private string _contentRating = string.Empty;
        public string ContentRating
        {
            get { return this._contentRating; }
            set { this.SetProperty(ref this._contentRating, value); }
        }

        private DateTime _datePublished;
        public DateTime DatePublished
        {
            get { return this._datePublished; }
            set { this.SetProperty(ref this._datePublished, value); }
        }
        public int YearPublished
        {
            get { return this._datePublished.Year; }
        }

        private MovieDataYear _yearGroup;
        public MovieDataYear YearGroup
        {
            get { return this._yearGroup; }
            set { this.SetProperty(ref this._yearGroup, value); }
        }

        private TimeSpan _duration;
        public TimeSpan Duration
        {
            get { return this._duration; }
            set { this.SetProperty(ref this._duration, value); }
        }

        private ImageSource _posterImage = null;
        private String _posterImagePath = null;
        public ImageSource PosterImage
        {
            get
            {
                if (this._posterImage == null && this._posterImagePath != null)
                {
                    this._posterImage = new BitmapImage(new Uri(MovieDataCommon._baseUri, this._posterImagePath));
                }
                return this._posterImage;
            }

            set
            {
                this._posterImagePath = null;
                this.SetProperty(ref this._posterImage, value);
            }
        }

        private IEnumerable<string> _genres;
        public IEnumerable<string> Genres
        {
            get { return this._genres; }
        }
    }

    /// <summary>
    /// Generic group data model.
    /// </summary>
    public class MovieDataYear : MovieDataCommon
    {
        public MovieDataYear(String uniqueId, String title, int year)
            : base(uniqueId, title)
        {
            this._value = year;
            Items.CollectionChanged += ItemsCollectionChanged;
        }

        private int _value;
        public int Value
        {
            get { return this._value; }
        }

        private void ItemsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            // Provides a subset of the full items collection to bind to from a GroupedItemsPage
            // for two reasons: GridView will not virtualize large items collections, and it
            // improves the user experience when browsing through groups with large numbers of
            // items.
            //
            // A maximum of 12 items are displayed because it results in filled grid columns
            // whether there are 1, 2, 3, 4, or 6 rows displayed

            switch (e.Action)
            {
                case NotifyCollectionChangedAction.Add:
                    if (e.NewStartingIndex < 12)
                    {
                        TopItems.Insert(e.NewStartingIndex, Items[e.NewStartingIndex]);
                        if (TopItems.Count > 12)
                        {
                            TopItems.RemoveAt(12);
                        }
                    }
                    break;
                case NotifyCollectionChangedAction.Move:
                    if (e.OldStartingIndex < 12 && e.NewStartingIndex < 12)
                    {
                        TopItems.Move(e.OldStartingIndex, e.NewStartingIndex);
                    }
                    else if (e.OldStartingIndex < 12)
                    {
                        TopItems.RemoveAt(e.OldStartingIndex);
                        TopItems.Add(Items[11]);
                    }
                    else if (e.NewStartingIndex < 12)
                    {
                        TopItems.Insert(e.NewStartingIndex, Items[e.NewStartingIndex]);
                        TopItems.RemoveAt(12);
                    }
                    break;
                case NotifyCollectionChangedAction.Remove:
                    if (e.OldStartingIndex < 12)
                    {
                        TopItems.RemoveAt(e.OldStartingIndex);
                        if (Items.Count >= 12)
                        {
                            TopItems.Add(Items[11]);
                        }
                    }
                    break;
                case NotifyCollectionChangedAction.Replace:
                    if (e.OldStartingIndex < 12)
                    {
                        TopItems[e.OldStartingIndex] = Items[e.OldStartingIndex];
                    }
                    break;
                case NotifyCollectionChangedAction.Reset:
                    TopItems.Clear();
                    while (TopItems.Count < Items.Count && TopItems.Count < 12)
                    {
                        TopItems.Add(Items[TopItems.Count]);
                    }
                    break;
            }
        }

        private ObservableCollection<MovieDataItem> _items = new ObservableCollection<MovieDataItem>();
        public ObservableCollection<MovieDataItem> Items
        {
            get { return this._items; }
        }

        private ObservableCollection<MovieDataItem> _topItem = new ObservableCollection<MovieDataItem>();
        public ObservableCollection<MovieDataItem> TopItems
        {
            get { return this._topItem; }
        }
    }

    /// <summary>
    /// Creates a collection of groups and items with hard-coded content.
    /// 
    /// SampleDataSource initializes with placeholder data rather than live production
    /// data so that sample data is provided at both design-time and run-time.
    /// </summary>
    public sealed class MoviesDataSource
    {
        private static MoviesDataSource _sampleDataSource = new MoviesDataSource();

        private ObservableCollection<MovieDataYear> _allGroups = new ObservableCollection<MovieDataYear>();
        public ObservableCollection<MovieDataYear> AllGroups
        {
            get { return this._allGroups; }
        }

        public static IEnumerable<MovieDataYear> GetGroups(string uniqueId)
        {
            if (!uniqueId.Equals("AllGroups")) throw new ArgumentException("Only 'AllGroups' is supported as a collection of groups");

            return _sampleDataSource.AllGroups;
        }

        public static MovieDataYear GetGroup(string uniqueId)
        {
            // Simple linear search is acceptable for small data sets
            var matches = _sampleDataSource.AllGroups.Where((group) => group.UniqueId.Equals(uniqueId));
            if (matches.Count() == 1) return matches.First();
            return null;
        }

        public static MovieDataItem GetItem(string uniqueId)
        {
            // Simple linear search is acceptable for small data sets
            var matches = _sampleDataSource.AllGroups.SelectMany(group => group.Items).Where((item) => item.UniqueId.Equals(uniqueId));
            if (matches.Count() == 1) return matches.First();
            return null;
        }
    }
}